Transition cows 2010
The transition period for the dairy cow is a key to a successful lactation and a successful dairy enterprise. This year I attended the American Dairy Science Association's Discover Conference entitled "Transition Cow: Biology and Management". The last time the conference focused on this topic was in 1999. Since that time, transition metabolic disease incidence has been reduced for some diseases, such as milk fever, but not for all of them. What else do we need to learn to reduce disease and mortality in early lactation even further?
Dry cows shouldn't be the forgotten group. During the dry period, a cow is beginning her next lactation and should be treated with care and offered comfortable facilities. The same goes for fresh cows. Cows in early lactation producing over 100 pounds of milk per day are certainly a miracle of modern biology. A dairy cow is a marvelous living engine, an extremely high performance athlete, an efficient producer of wholesome nutrition. The transition period is critical for her success.
Some of the highlights of the Transition Cow conference included discussion on the following questions:
- What is the optimal body condition score (BCS) for dry cows? Dr. Phil Garnsworthy, University of Nottingham, UK, suggested that cows calve with a BCS between 2.5 and 3.0 to optimize health, fertility, and lifetime performance. It is acceptable that cows lose 0.5 unit of BCS at calving. Most experts recommend a score of 3.25, so it was interesting to hear his perspective.
- Calving is not a disease: Can grouping strategies enhance dairy cow well-being? A question asked by Dr. Mark Fox, practicing veterinarian from Michigan. Some of his clients are using feeding/grouping strategies to minimize excessive weight gain in late lactation in order to reduce the incidence of metabolic problems in early lactation. It could be a practical solution for larger dairies having problems with over-conditioned cows.
- Should we control energy intake in dry cow diets? Dr. Jim Drackley, University of Illinois, presented evidence that the use of large amounts of cereal straw to dilute the energy content in dry cow diets has been effective in decreasing health problems in early lactation. The straw must be adequately processed to avoid sorting and cows must have adequate feed bunk space. Many farms have been successfully using single group dry cow management (40 to 45 day dry period) following the high fiber diet approach.
- Should we treat subclinical ketosis? Dr. Jerome Carrier, Quebec, Canada, indicated that some dairies perform ketosis screen-and-treat programs in fresh cows. However, a clinical study conducted while working on his Ph.D. at the University of Minnesota showed no positive effect of ketosis treatment on clinical endpoints such as displaced abomasum, milk yield, and reproductive performance. More research is needed to fully understand the how and why of ketosis development in order to reduce its negative effects.
- How to treat clinical ketosis? Dextrose? Propylene glycol? How much? Dr. Gary Oetzel, University of Wisconsin, suggested using 8 ounces of propylene glycol orally once a day for no more than 3 days for moderate cases. For more severe cases, use one-half to one bottle 50% dextrose IV with added vitamins no more than once daily for 3 days.
- What are some management risk factors associated with transition cow health? Dr. Ken Nordlund, University of Wisconsin, presented results on evaluating 50 Wisconsin herds using the Transition Cow Index (TCI). He found that risk factors associated with TCI scores were prefresh feed bunk space per cow, freestall base, size of freestalls, days in dynamic (cows moving in/out frequently) calving pens, fresh pen bunk space per cow, and disease screening methods.
- What should transition barns look like? Dr. Nordlund suggests that transition cow barns have 30 inches of feed bunk space per cow, deep-bedded stalls measuring 108+ inches long and 50+ inches wide for cow groups and 48 inches for heifer groups, and stable social grouping through the precalving period.
- What has been learned about the social and feeding behavior of the transition cow? Dr. Marina von Keyserlingk, University of British Columbia, summarized a series of research projects conducted by their group. She indicated that it is critical to provide adequate feed bunk access to all cows so that subordinate animals have the opportunity to eat a well balanced diet. Cows that had the greatest reduction in feeding time and dry matter intake in late dry period were at greatest risk of being sick after calving.
It appears that there is yet a lot to learn to optimize productivity and well-being of transition cows. Working with many commercial dairies across the region, I noticed that increased attention has been devoted to dry cows than in the past. It is a great step forward to see more producers understanding the importance of providing the best environment and care possible to this special group of animals.
Published in Dairy Star November 19, 2010